Felting needle with barb on a single edge and an isosceles blade

ABSTRACT

A felting needle having a needle body which in cross section is an isosceles triangle in which the equal sides are longer than the remaining side, or base, the altitude from the base to the most acute apex is about 20% greater than the base, and in which the apex angle between the equal sides is about 40* to 45*. The needle barbs are provided on that apex only.

United States Patent i1 1 Foster FELTING NEEDLE WITH BARB ON A SINGLE EDGE AND AN ISOSCELES BLADE [76] Inventor: Edson P. Foster, 409 S7 29th St.,

Manitowoc, Wis. 54220 [22] Filed: Jan. 6, 1975 [21] Appl. N0.: 538,649

[52] US. Cl 28/4 N [51] Int. Cl. D041! 18/00 [58] Field of Search 28/4 R, 4 N, 72.2 R

[56] References Cited UNITED STATES PATENTS 3,230,599 1/1966 McKew et al 28/4 N 3,762,004 10/1973 Shepard et al 28/4 N FOREIGN PATENTS OR APPLICATIONS 233,141 3/1961 Australia 28/4 N [451 Oct. 21, 1975 2/1960 United Kingdom 28/4 N l/1972 Japan 28/4 N Primary Examiner-Louis Rimrodt Attorney, Agent, or Firm-Wheeler, Morsell, House & Fuller [5 7 ABSTRACT A felting needle having a needle body which in cross section is an isosceles triangle in which the equal sides are longer than the remaining side, or base, the altitude from the base to the most acute apex is about 20% greater than the base, and in which the apex angle between the equal sides is about 40 to 45. The needle barbs are provided on that apex only.

9 Claims, 4 Drawing Figures US. Patent Oct. 1975 1 9 FELTING NEEDLE WITH BARB ON A SINGLE EDGE AND AN ISOSCELES BLADE BACKGROUND OF INVENTION The present invention relates to improvements in felting needles. Needles having barbs in only a single plane are known, for instance, in Sitterson Canadian Pat. No. 732,806; Zocher US. Pat. No. 3,464,097; Foster U.S. Pat. No. 2,327,416; and Foster U.S. Pat. No. 3,479,708. So far as is known only the Sitterson patent discloses a cross-sectional shape which may be described as an isosceles triangle (FIG. 2), and that disclosure appears accidental since FIG. 2 is described as a conventional triangular needle, which would be equilateral, and since the deviation from such a triangle is small. The Sitterson needle shows barbs at all three edges, without recognition that his assymetrical edges are unsuitable for barbing. His disclosure shows major deviations from standard barbs in FIG. 2, and is not described in the text of the Sitterson patent.

No known prior art describes a needle having the strength and depth of throat of the needle of my invention.

It is common practice in art today to provide felting needles for special purposes with a barb or barbs in only one longitudinally extending edge of a conventional equilateral triangular blade.

This has the disadvantage-that the barb throat capacity and barb size are limited by the limited height of the altitude through the vertex of the 60 edge into which the barb is formed. I

An additional disadvantage in barbing only one edge of a triangular blade configuration suitable for the barbing of three edges, is that the strength through the two unbarbed edges is greatly increased while the one barbed edge where the stress of needling will be concentrated remains no stronger than before.

Accordingly, it is the object of the present invention to provide an improved blade for a felting needle of substantially isosceles triangular cross-sectional configuration having only one longitudinally extending ridge or apex of bilateral symmetry suitable for barb formation, and the cross-sectional altitude through the vertex of said ridge to the end wall opposite said ridge being oversize to provide adequate strength and barb carrying capacity and the end wall or base being correspondingly undersize in width, to compensate for the structural strength it will not need since it has no barbs.

DEFINITIONS For ease of identification the following definitions apply herein. The cross section of the blade of the felting needle of my invention is an isosceles triangle having a pair of equal sides and a narrower side. The narrow side will be called the base and the equal sides will be called sides. The angles at which the sides meet the base will be called corners, while the angle at which the sides meet each other will be called the apex" or ridge. Both the corners and the ridge extend substantially the length of the blade, or working portion of the needle. The isosceles triangle defined has its greatest altitude from the base to the apex, or ridge, and the unqualified word altitude refers to that, while the terms major altitude and minor altitude will be used to distinguish between the base-apex altitude and shorter altitudes, respectively. The throat depth" is the measurement from the apex to the bottom of the throat; kickup or projection is the height from apex to the tip of the barb. Total barb depth includes both throat depth and projection. A nominal measurement is taken to the sharp apex or corner of a theoretical triangle, as distinguished from actual measurements taken on real blades having slightly rounded apexes and corners. I

SUMMARY OF THE INVENTION i the narrow apex is greater than about 120% of the width of the narrow base. When the apex is 45 the nominal altitude is 120% of the nominal base; at smaller apex angles such as the actual altitude will also be 120% of the actual base. Another way of defining'my invention is that the equal sides of the isosceles triangle converge at an angle no greater than about When the barb and throat are formed into the apex of the defined narrow isosceles triangle formed by the converging equal sides, a number of substantial advantages are present which would not be present in other configurations of triangular bodies or blades on a felting needle. On a felting needle blade or body, the provi-' sion of barbs in a single apex of the blade substantially asymmetrically weakens the blade. In my isosceles cross-section blade, the altitude from the base or short side to the most acute angle or apex is sufficient so that in forming the barb and the throat the body or blade of the needle is not substantially weakened, because the barb is primarily in the narrowest portion while the remaining portion of the body where the major part of the material lies is not notched. In addition, the barbs and throats are more readily formed as they should be, because they are formed only in that portion of the blade which has bilateral symmetry. Were the barbs to be formed in the corners where the short side joins the longer sides the forming would have to be done with the needle resting on one of the longer sides, presenting the apex asymmetrically to the forming die. The resulting barbs and throats would not have the proper symmetrical configuration. Still another advantage of my invention is the fact that in the narrow blade less material is pushed out at the sides of the blade in forming the throat, giving a smoother configuration to the needle blade or body. Finally, the barb height attainable using the blade shape of my invention is much greater and the throat may be made much deeper for greater capacity than can be produced on a conventional blade, without weakening the blade unduly.

DESCRIPTION OF DRAWINGS FIG. 1 is aside view of a felting needle.

FIG. 2 is a greatly enlarged side view of the throat and barb portion of the needle.

FIG..3 is a cross-sectional view on line 33 of FIG. 2 showing the isosceles cross section of the blade according to my invention.

FIG. 4 is a view like FIG. 3 except that the crosssectional shape of the blade is modified.

DETAILED DESCRIPTION OF THE EMBODIMENT SECTION Although the disclosure. hereof isdetailed and exact to enable those skilled in the art to practice the invention, the physical embodiments herein disclosed merely exemplify the invention which may be embodied in other specific structure. While the best known embodiment has been described, the details may be changed without departing from the invention, which is defined by the claims. I

My felting needle "consists of a shank portion having a crank 12 whereby the needle is secured in a fixture such as a needle board, a number of such needles being contained in a given fixture. The needle is pro vided with a blade portion l4 and with a somewhat rounded or pointed tip 16.

As best shown inFIG. 3, the blade or body, 14 has the form of an isosceles triangle in cross-sectional area. The blade 14 has a short base and a pair of sides 22 of equal length joining base 20 with apex 24. Two additionalcorners 26 join the base 20 to the sides 22. Although the, apex and corners will be discussed as though they were true angles, in practice, they are slightlyrounded. The amount of rounding may vary according to manufacturing practices.

In a manner whichis well known to the art, one or more barbs .28 having throat 30 are formed in apex or ridge24 only of blade 14, preferably by resting the base 20; of ,the blad e on a surface and striking the apex 24 with,a,die in conventional fashion. I

when fqifmingsuch a barb 28 on an equilateral triangular. blade, itis rarely possible to form a throat which is more than 30% of the altitude of the original blade to the apex in which the throat and barb are being formed. In my isosceles blade- 14, in which the sides of the apex 24 being formed include an angle of approximately 40 to 45, theapex being formed contains less material and offers less resistance to the forming die. Accordingly, it is possible to form approximately 40% of the original altitude, giving greater throat depth. I For example, in'a blade formed from 0.032 inch wire, for a 25 gauge needle, having (in nominal dimensions) an apex of 45 where the barb 28 is to be formed, and 67,5" corners, the nominal altitude of the blade is approximately .044 inches, the nominal base .0365 inches, and the throat may be struck to a depth of .0176 inches below the apex to give a total barb depth of .022 inches including the kickup of the barb above the apex or ridge (FIG. 2) by the die. Had the blade been an equilateral triangle with a 60 apex it would rarely bejpossible to form a throat having a depth more than 30% of the original smaller altitude because of the rapid increase of the width of the blade as the die enters the apex. Therefore the barb and throat would be much smaller and less effective for felting. For instance, in a 60 equilateral blade formed from the same wire size (in the illustration .032 inches diameter for a 25 gauge needle) the total area of the blade would be the same, but in theoretical dimensions the base would be about .0426 inches, the altitude would be about .0375 inches, and the barb depth can be little more than about .012 inches total depth from the bottom of the throat to the top of the ba'rb. The total barb depth of .022 inches inches in my isosceles blade has far greater capacity.

Because in my isosceles blade the major part of the material is near the base, such a deep barb does not unduly weaken the blade. This is particularly true since barbs are provided only on the single most acute apex.

The deep throat gives much greater throat capacity and hence, improves felting efficiency. I have found that these advantages are attained primarily when the angle of the apex in which the barbs'are formed is between 40" and 45. To put the matter another way, the nominal altitude should be not substantially less than of the width of the nominal base of the isosceles triangle. In preferred form the actual altitude'is at least 120% of the actual base. Within the range the proportions of the blade are such as to give rise to the advantages described.

FIG. 4 shows the broadest base compatible with this invention. The apex is 45 and the base corners are 67.5. In such a triangle the altitude is 20% larger than the base if the measurements are made on a nominal v basis. However the invention also includes cases in which real measurements to rounded comers show the altitude to be 120% of the base. In FIG. 4 the reference characters correspond to those above except that the altitude is labelled 320 to indicate that it is proportionally as short as permitted by my invention. The throat depth is shown as shallower, to indicate that a range of throat depths is permissible, though the capability for very great throat depths and total barb heights is an important aspect of the invention.

l. A felting needle blade portion of substantially isosceles triangular cross-sectional configuration, comprising only one longitudinally extending ridge formed by bilaterally symmetrical major side walls converging laterally at an apex and being interconnected at their edges by the base of said triangular blade portion, the major altitude of said triangle being at least 20% greater than said base, and a throat and barb formed only in said longitudinally extending ridge of said major altitude. g

2. The device of claim 1 in which the throat extends to a depth of at least 30% of the altitude of the triangle.

3. The device of claim 1 in which the dimensions are nominal dimensions.

4. The device of claim 1 in which the dimensions are actual dimensions.

5. The device of claim 1 in which the distancefrom the tip of the barb to the bottom of the throat is substantially one-half of the altitude of the triangle from the apex to the base.

6. In a felting needle, a blade having an isosceles triangular cross section, the base of said isosceles triangle being shorter than the sides, at least one felting barb and associated throat being formed at the apex of said triangle, the apex of said triangle being not greater than 7. The device of claim 6 in which the nominal altitude of said triangle is not less than about 120% of said width of the base of the triangle.

8. The device of claim 6 in which said apex in which the barbs are formed forms an angle in the range 40 9. The device of claim 6 in which the throat is at least 40% as deep as the altitude of said triangle. 

1. A felting needle blade portion of substantially isosceles triangular cross-sectional configuration, comprising only one longitudinally extending ridge formed by bilaterally symmetrical major side walls converging laterally at an apex and being interconnected at their edges by the base of said triangular blade portion, the major altitude of said triangle being at least 20% greater than said base, and a throat and barb formed only in said longitudinally extending ridge of said major altitude.
 2. The device of claim 1 in which the throat extends to a depth of at least 30% of the altitude of the triangle.
 3. The device of claim 1 in which the dimensions are nominal dimensions.
 4. The device of claim 1 in which the dimensions are actual dimensions.
 5. The device of claim 1 in which the distance from the tip of the barb to the bottom of the throat is substantially one-half of the altitude of the triange from the apex to the base.
 6. In a felting needle, a blade having an isosceles triangular cross section, the base of said isosceles triangle being shorter than the sides, at least one felting barb and associated throat being formed at the apex of said triangle, the apex of said triangle being not greater than 45*.
 7. The device of claim 6 in which the nominal altitude of said triangle is not less than about 120% of said width of the base of the triangle.
 8. The device of claim 6 in which said apex in which the barbs are formed forms an angle in the range 40* to 45*.
 9. The device of claim 6 in which the throat is at least 40% as deep as the altitude of said triangle. 